I am a Canadian citizen/ US permanent resident (PR), my wife is an American citizen. We are looking into moving to BC. My wife is currently an RN in the states and has already begun the application process for getting her license in BC. We are wondering what paperwork we need to have done when we show up at the border. My wife is not necesarily planning on immigrating immediately as this is a trial to see if we want to stay in Canada.

Without PR status, all your wife is allowed to do at this time is come to Canada as a visitor / tourist. There is no paperwork for her to complete when she enters as a tourist since she is American and is visa exempt (i.e. she can visit Canada on her passport alone and doesn't require a visa).

She cannot "move" here or "live" here. You need to be careful entering Canada and make sure it's clear (in both what your wife does and says) that she is only entering as a visitor and has no plans to stay long term. Remember that if and for how long your wife is allowed into Canada is up to the individual immigration officer she encounters at the border. So if asked, she needs to convince this individual that she is a genuine visitor.

How are you planning on entering Canada? If you are driving across the border with signficant personal belonging - it will look like your wife is coming here long term. In that case it would be smart for you to drive the vehicle across alone and for your wife to travel separately (perferably to fly in with just a suitcase and a return flight - just like a real tourist would). Your wife should also carry evidence with her that demonstrates she has ties to the US (property owned, job, assets) since this will further prove she is only entering Canada as a tourist.

I would encourage you to stop thinking and talking as if your wife is "moving" to Canada since she's not allowed to do that. Program yourselves now to call it "visiting". You don't want to accidentally say "moving" to an immigration officer. Hope this helps.